Artigos de revistas: "Lignine sulfatée"

1

Penín, Lucía, Heiko Lange, Valentín Santos, Claudia Crestini e Juan Carlos Parajó. "Characterization of Eucalyptus nitens Lignins Obtained by Biorefinery Methods Based on Ionic Liquids". Molecules 25, n.º 2 (20 de janeiro de 2020): 425. http://dx.doi.org/10.3390/molecules25020425.

Texto completo da fonte

Resumo:

Eucalyptus nitens wood samples were subjected to consecutive stages of hydrothermal processing for hemicellulose solubilization and delignification with an ionic liquid, i.e., either 1-butyl-3-methylimidazolium hydrogen sulfate or triethylammonium hydrogen sulfate. Delignification experiments were carried out a 170 °C for 10–50 min. The solid phases from treatments, i.e., cellulose-enriched solids, were recovered by centrifugation, and lignin was separated from the ionic liquid by water precipitation. The best delignification conditions were identified on the basis of the results determined for delignification percentage, lignin recovery yield, and cellulose recovery in solid phase. The lignins obtained under selected conditions were characterized in deep by 31P-NMR, 13C-NMR, HSQC, and gel permeation chromatography. The major structural features of the lignins were discussed in comparison with the results determined for a model Ionosolv lignin.

Estilos ABNT, Harvard, Vancouver, APA, etc.

2

Levdansky, Alexander V., Natalya Yu Vasilyeva, Yuriy N. Malyar, Alexander A. Kondrasenko, Olga Yu Fetisova, Aleksandr S. Kazachenko, Vladimir A. Levdansky e Boris N. Kuznetsov. "An Efficient Method of Birch Ethanol Lignin Sulfation with a Sulfaic Acid-Urea Mixture". Molecules 27, n.º 19 (26 de setembro de 2022): 6356. http://dx.doi.org/10.3390/molecules27196356.

Texto completo da fonte

Resumo:

For the first time, the process of birch ethanol lignin sulfation with a sulfamic acid-urea mixture in a 1,4-dioxane medium was optimized experimentally and numerically. The high yield of the sulfated ethanol lignin (more than 96%) and containing 7.1 and 7.9 wt % of sulfur was produced at process temperatures of 80 and 90 °C for 3 h. The sample with the highest sulfur content (8.1 wt %) was obtained at a temperature of 100 °C for 2 h. The structure and molecular weight distribution of the sulfated birch ethanol lignin was established by FTIR, 2D 1H and 13C NMR spectroscopy, and gel permeation chromatography. The introduction of sulfate groups into the lignin structure was confirmed by FTIR by the appearance of absorption bands characteristic of the vibrations of sulfate group bonds. According to 2D NMR spectroscopy data, both the alcohol and phenolic hydroxyl groups of the ethanol lignin were subjected to sulfation. The sulfated birch ethanol lignin with a weight average molecular weight of 7.6 kDa and a polydispersity index of 1.81 was obtained under the optimum process conditions. Differences in the structure of the phenylpropane units of birch ethanol lignin (syringyl-type predominates) and abies ethanol lignin (guaiacyl-type predominates) was manifested in the fact that the sulfation of the former proceeds more completely at moderate temperatures than the latter. In contrast to sulfated abies ethanol lignin, the sulfated birch ethanol lignin had a bimodal and wider molecular weight distribution, as well as less thermal stability. The introduction of sulfate groups into ethanol lignin reduced its thermal stability.

Estilos ABNT, Harvard, Vancouver, APA, etc.

3

Malyar, Yuriy Nikolayevich, Natal'ya Yur'yevna Vasil'yeva, Aleksandr Sergeyevich Kazachenko, Galina Pavlovna Skvortsova, Irina Vladimirovna Korol'kova e Svetlana Alekseyevna Kuznetsova. "SULFATION OF ABIES ETHANOL LIGNIN WITH COMPLEXES OF SULFUR TRIOXIDE WITH 1,4-DIOXANE AND PYRIDINE". chemistry of plant raw material, n.º 3 (22 de outubro de 2020): 5–15. http://dx.doi.org/10.14258/jcprm.2020036931.

Texto completo da fonte

Resumo:

In this work, we optimized the process of sulfating abies ethanol lignin with complexes of sulfuric anhydride with pyridine and 1,4-dioxane. Experimentally found are the conditions for the implementation of the process of sulfation of abies ethanol lignin by complexes of sulfur trioxide with 1,4-dioxane and pyridine, providing a high sulfur content (12.0–12.6%). It was shown that a high sulfur content of 12.0–13.5% (mass.) in the obtained ethanol lignin sulfate is achieved when the ratio of the amount of chlorosulfonic acid to the amount of abies ethanol lignin is 20.22 : 1 mmol : g and the duration of the sulfation process is 60–120 min and independent of the nature of the sulfating complex. The structure and composition of water-soluble sulfated abies ethanol lignin are confirmed by FTIR spectroscopy, gel permeation chromatography and elemental analysis. In the FTIR spectra of sulfated abies ethanol lignin, in comparison with the FTIR spectra of the initial abies ethanol lignin, there are absorption bands in the region of 1270–1260, 1220–1212, 861–803 cm-1, corresponding to vibrations of sulfate groups. Compared to the initial lignin, sulfated abies ethanol lignin has a low degree of polydispersity. In particular, there was an increase in Mw c ~1.5 kDa to ~3.4 kDa in lignin sulfated for 30 min and a decrease in polydispersity from 2.59 to 1.22 compared to the initial abies ethanol lignin. With an increase in the sulfation time, the profile of the molecular mass distribution curve shifts to a high molecular weight region, with a simultaneous increase in polydispersity to 1.5 and Mw increases to ~4.3 kDa.

Estilos ABNT, Harvard, Vancouver, APA, etc.

4

Arrieta, Alberto Albis, Ever Ortiz Muñoz, Ismael Piñeres Ariza, Juan Osorio Cardozo e Jennifer Monsalvo Morales. "Catalytic effect of ferric sulfate and zinc sulfate on lignin pyrolysis". Applied Chemical Engineering 5, n.º 1 (26 de abril de 2022): 59. http://dx.doi.org/10.24294/ace.v5i1.1449.

Texto completo da fonte

Resumo:

The effect of zinc sulfate and ferric sulfate on the pyrolysis process of lignin was studied at three different heating rates by using the thermogravimetric analysis technique. It was found that the pyrolysis of pure lignin is barely affected with the change of heating rates between 10 to 100 °C/min, which is unexpected because of the kinetic nature of pyrolysis. The pyrolysis kinetics of this major component of biomass was studied by using three fitting methods: the differential method with reaction order model n, the isoconversional method, and the distribution of activation energies model, DAEM. The best fit, which allowed calculating acceptable kinetic parameters, was obtained using the last method. The results show the influence of the catalysts and the heating rate on the lignin pyrolysis processes in the presence of the sulfates under study, which is confirmed by obtaining different kinetic parameters. The results suggest that zinc sulfate and ferric sulfate change the kinetic mechanism of lignin pyrolysis.

Estilos ABNT, Harvard, Vancouver, APA, etc.

5

Belesov, Artyom V., Anton V. Ladesov, Ilya I. Pikovskoi, Anna V. Faleva e Dmitry S. Kosyakov. "Characterization of Ionic Liquid Lignins Isolated from Spruce Wood with 1-Butyl-3-methylimidazolium Acetate and Methyl Sulfate and Their Binary Mixtures with DMSO". Molecules 25, n.º 11 (27 de maio de 2020): 2479. http://dx.doi.org/10.3390/molecules25112479.

Texto completo da fonte

Resumo:

Ionic liquids (ILs) based on 1-butyl-3-methylimidazolium (bmim) cation have proved to be promising solvents for the fractionation of plant biomass with the production of cellulose and lignin. This study deals with the characterization of lignins isolated from coniferous (spruce) wood using [bmim]OAc and [bmim]MeSO4 ionic liquids and their binary mixtures with DMSO (80:20). Molecular weight distributions, functional composition, and structural features of IL lignins were studied by size-exclusion chromatography, NMR spectroscopy (1D and 2D) and atmospheric pressure photoionization high-resolution mass spectrometry. It was shown that the interaction of ILs with lignin leads to significant chemical changes in the biopolymer; a decrease in the degree of polymerization and in the content of free phenolic hydroxyl groups due to alkylation, the disappearance (in the case of [bmim]OAc) of carbonyl groups and a significant destruction of β-O-4 bonds. The chemical reactions between lignin and 1-butyl-3-methylidazolium cation with covalent binding of ionic liquids or products of their decomposition is evidenced by the presence of a large number of nitrogen-containing oligomers in IL lignins.

Estilos ABNT, Harvard, Vancouver, APA, etc.

6

Albis Arrieta, Alberto Ricardo, Ever Ortiz Muñoz, Ismael Enrique Piñeres Ariza, Juan Sebastián Osorio Cardozo e Jennifer Monsalvo Morales. "Efecto catalítico del sulfato de zinc y el sulfato férrico en la pirólisis de la lignina/Catalytic effect of zinc sulfate and ferric sulfate on lignin pyrolysis". Prospectiva 16, n.º 1 (12 de dezembro de 2017): 41–50. http://dx.doi.org/10.15665/rp.v16i1.1397.

Texto completo da fonte

Resumo:

Recurriendo al uso de la técnica análisis termogravimétrico, se estudió el efecto del sulfato de zinc y del sulfato férrico en el proceso de pirólisis de la lignina a tres velocidades de calentamiento. Se encontró que la pirólisis de la lignina pura se afecta muy poco con el cambio de las velocidad de calentamiento entre 10 y 100 °C/min, lo cual es inesperado por la naturaleza cinética de la pirólisis. La cinética de pirólisis de este componente de la biomasa fue estudiada teniendo en cuenta tres métodos de ajuste: el método diferencial con modelo de orden de reacción n, el método isoconversional y el modelo de distribución de energías de activación, DAEM. Los mejores ajustes, que permitieron calcular parámetros cinéticos aceptables, fueron obtenidos usando el último método. Los resultados evidencian la influencia de los catalizadores y de la velocidad de calentamiento en los procesos de pirólisis de la lignina en presencia de los sulfatos de estudio, que se confirma con la obtención de diferentes parámetros cinéticos. En términos generales, los sulfatos de zinc y férrico retardan el proceso de pirólisis de la lignina. Los resultados sugieren que los sulfatos de zinc y férrico cambian el mecanismo cinético de la pirólisis de la lignina.

Estilos ABNT, Harvard, Vancouver, APA, etc.

7

Martínez-Cortés, Teresa, Federico Pomar e Esther Novo-Uzal. "Evolutionary Implications of a Peroxidase with High Affinity for Cinnamyl Alcohols from Physcomitrium patens, a Non-Vascular Plant". Plants 10, n.º 7 (19 de julho de 2021): 1476. http://dx.doi.org/10.3390/plants10071476.

Texto completo da fonte

Resumo:

Physcomitrium (Physcomitrella) patens is a bryophyte highly tolerant to different stresses, allowing survival when water supply is a limiting factor. This moss lacks a true vascular system, but it has evolved a primitive water-conducting system that contains lignin-like polyphenols. By means of a three-step protocol, including ammonium sulfate precipitation, adsorption chromatography on phenyl Sepharose and cationic exchange chromatography on SP Sepharose, we were able to purify and further characterize a novel class III peroxidase, PpaPrx19, upregulated upon salt and H2O2 treatments. This peroxidase, of a strongly basic nature, shows surprising homology to angiosperm peroxidases related to lignification, despite the lack of true lignins in P. patens cell walls. Moreover, PpaPrx19 shows catalytic and kinetic properties typical of angiosperm peroxidases involved in oxidation of monolignols, being able to efficiently use hydroxycinnamyl alcohols as substrates. Our results pinpoint the presence in P. patens of peroxidases that fulfill the requirements to be involved in the last step of lignin biosynthesis, predating the appearance of true lignin.

Estilos ABNT, Harvard, Vancouver, APA, etc.

8

Kazachenko, Aleksandr S., Feride Akman, Natalya Yu Vasilieva, Yuriy N. Malyar, Olga Yu Fetisova, Maxim A. Lutoshkin, Yaroslava D. Berezhnaya, Angelina V. Miroshnikova, Noureddine Issaoui e Zhouyang Xiang. "Sulfation of Wheat Straw Soda Lignin with Sulfamic Acid over Solid Catalysts". Polymers 14, n.º 15 (25 de julho de 2022): 3000. http://dx.doi.org/10.3390/polym14153000.

Texto completo da fonte

Resumo:

Soda lignin is a by-product of the soda process for producing cellulose from grassy raw materials. Since a method for the industrial processing of lignin of this type is still lacking, several research teams have been working on solving this problem. We first propose a modification of soda lignin with sulfamic acid over solid catalysts. As solid catalysts for lignin sulfation, modified carbon catalysts (with acid sites) and titanium and aluminum oxides have been used. In the elemental analysis, it is shown that the maximum sulfur content (16.5 wt%) was obtained with the Sibunit-4® catalyst oxidized at 400 °C. The incorporation of a sulfate group has been proven by the elemental analysis and Fourier-transform infrared spectroscopy. The molecular weight distribution has been examined by gel permeation chromatography. It has been demonstrated that the solid catalysts used in the sulfation process causes hydrolysis reactions and reduces the molecular weight and polydispersity index. It has been established by the thermal analysis that sulfated lignin is thermally stabile at temperatures of up to 200 °C. According to the atomic force microscopy data, the surface of the investigated film consists of particles with an average size of 50 nm. The characteristics of the initial and sulfated β-O-4 lignin model compounds have been calculated and recorded using the density functional theory.

Estilos ABNT, Harvard, Vancouver, APA, etc.

9

Ferreira, Bruno G., Renan Falcioni, Lubia M. Guedes, Sofia C. Avritzer, Werner C. Antunes, Luiz A. Souza e Rosy M. S. Isaias. "Preventing False Negatives for Histochemical Detection of Phenolics and Lignins in PEG-Embedded Plant Tissues". Journal of Histochemistry & Cytochemistry 65, n.º 2 (12 de novembro de 2016): 105–16. http://dx.doi.org/10.1369/0022155416677035.

Texto completo da fonte

Resumo:

Polyethylene glycol (PEG) is a low-cost and advantageous embedding medium, which maintains the majority of cell contents unaltered during the embedding process. Some hard or complex plant materials are better embedded in PEG than in other usual embedding media. However, the histochemical tests for phenolics and lignins in PEG-embedded plant tissues commonly result in false negatives. We hypothesize that these false negatives should be prevented by the use of distinct fixatives, which should avoid the bonds between PEG and phenols. Novel protocols for phenolics and flavanols detection are efficiently tested, with fixation of the samples in ferrous sulfate and formalin or in caffeine and sodium benzoate, respectively. The differentiation of lignin types is possible in safranin-stained sections observed under fluorescence. The Maule’s test faultlessly distinguishes syringyl-rich from guaiacyl- and hydroxyphenyl-rich lignins in PEG-embedded material under light microscopy. Current hypothesis is corroborated, that is, the adequate fixation solves the false-negative results, and the new proposed protocols fill up some gaps on the detection of phenolics and lignins.

Estilos ABNT, Harvard, Vancouver, APA, etc.

10

Rotondo, Felipe, Rodrigo Coniglio, Leandro Cantera, Ignacio Di Pascua, Leonardo Clavijo e Andrés Dieste. "Lignin-based coatings for controlled P-release fertilizer consisting of granulated simple superphosphate". Holzforschung 72, n.º 8 (26 de julho de 2018): 637–43. http://dx.doi.org/10.1515/hf-2017-0176.

Texto completo da fonte

Resumo:

AbstractA novel lignin-based slow release fertilizer with low environmental impact has been developed. More precisely, a granulated simple superphosphate fertilizer, consisting of calcium phosphate monobasic [Ca(H2PO4)2·H2O] and gypsum (CaSO4·2H2O) was coated with modified kraft lignins and the diffusion of phosphorus was observed as a function of time. The lignin was hydroxymethylated with formaldehyde and subsequently cross-linked with phenol-formaldehyde resin resulting in HML-PF as coating. Moreover, coating films were prepared from a mixture of acetylated lignin (Lac) and acetylated cellulose (Cellac). Both coatings show similar permeability to calcium phosphate and controlled effectively the P-release, particularly at the initial stages of the experiment. The P-release was linear in the decay phase but there is no lag time in the process. A significant P amount was not released from the particles coated with HML-PF, i.e. 80–50% remained irreversible bound, depending on the coating formulation. The maximum fractional P-release varied among the different coatings tested. Phosphorus is partly retained inside the slightly soluble calcium sulfate matrix.

Estilos ABNT, Harvard, Vancouver, APA, etc.

11

Emrick, Rachel, D. L. Creech e G. Bickerstaff. "INFLUENCE OF LIGNITE-ACTIVATED WATER ON SEED GERMINATION, CUTTING PROPAGATION, AND PLANT PERFORMANCE". HortScience 31, n.º 5 (setembro de 1996): 744a—744. http://dx.doi.org/10.21273/hortsci.31.5.744a.

Texto completo da fonte

Resumo:

This project tested rates of lignite-activated water (LAW) for its influence on seed germination, cutting propagation, and plant performance. LAW is a product of CAW Industries, Rapid City, S.D. LAW is water-activated by lignite in a process that includes the addition of sulfated castor oil, calcium chloride, magnesium sulfate, sodium meta silicate, and fossilized organics from refined lignite. LAW is reported to improve many plant performance traits. Four rates were used in this study. Seed germination trials indicated no significant differences in germination percentage with LAW applications with the two species tested, Echinacea purpurea and Hibiscus dasycalyx. In a “closed” system, LAW enhanced cutting propagation success of Aster caroliniana, Cuphea micropetala, and Verbena `Homestead Purple', as measured by percent rooting and dry weight of roots produced. Cutting propagation of two woody species, Illicium henryi and Rosa banksiae, was not improved with LAW additions. In the SFASU Arboretum, pansy performance, as measured by plant dry weight, was improved one month after establishment.

Estilos ABNT, Harvard, Vancouver, APA, etc.

12

Morandim-Giannetti, Andreia de Ara�jo, Lidiane Gaspareto Felippe, V�nia Aparecida de Freitas Formenton Macedo Dos Santos, Massuo Jorge Kato e Maysa Furlan. "Phenylalanine ammonia lyase: new insights from Piperaceae species". Ecl�tica Qu�mica Journal 47, n.º 2SI (17 de agosto de 2022): 67–82. http://dx.doi.org/10.26850/1678-4618eqj.v47.2si.2022.p67-82.

Texto completo da fonte

Resumo:

The enzyme PAL (phenylalanine ammonia lyase) mediates the key entry point to the general phenylpropanoid pathway, which is involved in the lignification process and in the formation of a myriad of secondary compounds in plants that show a variety of biological activities. Soluble fractions containing PAL extracted from Piper and Peperomia species had the optimal catalytic activity analyzed by statistical design model. This analysis revealed that the best conversion of L-phenylalanine to trans-cinnamic acid was pH 9.3 and 58 °C after 25 h, corroborating interesting thermal stability. Additionally, the pre-purification of PAL using ammonium sulfate precipitation (25-55%) increased its specific activity, approximately 133% in P. aduncum and more than 900% in P. crassinervium. The content of lignin was higher for P. tuberculatum (25.71%), while only a small amount of lignin was observed in Peperomia blanda (11.95%). It is interesting to note that Peperomia plants are succulent and without significant amounts of lignin. However, the phenylpropanoid biosynthetic pathway is apparently addressed to produce predominantly tetrahydrofuran lignans with biological interest.

Estilos ABNT, Harvard, Vancouver, APA, etc.

13

Bouissil, Soukaina, Zainab El Alaoui-Talibi, Guillaume Pierre, Halima Rchid, Philippe Michaud, Cédric Delattre e Cherkaoui El Modafar. "Fucoidans of Moroccan Brown Seaweed as Elicitors of Natural Defenses in Date Palm Roots". Marine Drugs 18, n.º 12 (26 de novembro de 2020): 596. http://dx.doi.org/10.3390/md18120596.

Texto completo da fonte

Resumo:

Fucoidans from Moroccan brown seaweed Bifurcaria bifurcata and Fucus spiralis were tested for their elicitor activity after their purification and complete characterization. The fucoidans of B. bifurcata (BBF) and of F. spiralis (FSF) were extracted and purified then characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and size exclusion chromatography. The results show that BBF and FSF are mainly sulfated with 45.49 and 49.53% (w/w) sulfate, respectively. Analysis of neutral sugars determined by gas chromatography–mass spectrometry showed that FSF and BBF were mainly composed of 64% and 91% fucose and 20% and 6% galactose, respectively, with a few other sugars such as glucose (8% in FSF), rhamnose (1% in BBF) and mannose (8% in FSF and, 2% in BBF). The eliciting activity of these sulfated polysaccharides in stimulating the natural defenses of the date palm was evaluated through the activity of phenylalanine ammonia-lyase (PAL), and the increase in phenols and lignin content in the roots. The results obtained clearly show that the two fucoidans early and intensely stimulate the natural defenses of the date palm after 24 h of treatments. This remarkable elicitor effect seems to be linked to the sulfated groups compared to non-sulfate alginates extracted from the same algae. These results open promising perspectives for a biological control approach against date palm diseases.

Estilos ABNT, Harvard, Vancouver, APA, etc.

14

Pareek, S., J. I. Azuma, S. Matsui e Y. Shimizu. "Degradation of lignin and lignin model compound under sulfate reducing condition". Water Science and Technology 44, n.º 2-3 (1 de julho de 2001): 351–58. http://dx.doi.org/10.2166/wst.2001.0789.

Texto completo da fonte

Resumo:

The release of depolymerization products of lignin during the degradation of lignocellulsic material under sulfate reducing condition was investigated. In addition, we investigated the fate of the most common (β-O-4) link present in lignin under sulfate reducing condition, using a lignin model compound. The method of investigation was based on the selective inhibition of microbial uptake of released aromatic phenolic compounds, depolymerization product of lignin, by toluene. Eight different aromatic phenolic compounds were identified. Until day 17 only 3 phenolic compounds were regularly detected, thereafter 7 aromatic phenolic compounds could be regularly identified. The accumulation of identified phenolic acid was not linear with time. The lignin model compound was completely degraded within 13 days when either Avicel cellulose or newspaper was present as alternate source of carbon. On the other hand when lignin model compound was present as the sole source of carbon, it took more than 22 days for its complete degradation. But in either case complete degradation of lignin model compound was observed. Four degradation by-products of lignin model compound were identified, but the two most significant compounds identified were vanillic acid and 3-methoxy-4-hydroxy benzene propionic acid. The GC/MS analysis of the degradation by products of lignin model compound indicated that β-O-4 link was cleaved under sulfate reducing condition and the presence of additional carbon source enhanced this process.

Estilos ABNT, Harvard, Vancouver, APA, etc.

15

Bobei, Vasile, Daniela-Ionela Ciolea e Tiberiu Rusu. "Research on Water Quality Indicators at the Rovinari Power Plant". Mining Revue 29, n.º 3 (1 de setembro de 2023): 60–67. http://dx.doi.org/10.2478/minrv-2023-0024.

Texto completo da fonte

Resumo:

Abstract Indicators of: pH, temperature, conductivity, filtered residue at 105°C, suspended matter, ammonium, chemical oxygen consumption-CCOCr, chlorides, biochemical oxygen consumption - CBO5, sulfates, extractable substances with organic solvents, petroleum products, total iron, calcium, magnesium, sulfides and hydrogen sulfide. The excesses recorded in the sulfate and ammonium indicators in the phreatic waters within the unit premises and in the area of the slag and ash deposits are mainly due to natural causes and to a small extent to anthropogenic action. In accordance with the specialized literature, but also with the studies and research carried out, it is found that the exceedances recorded in the Oltenia area of the specified indicators are due to:- for ammonium (NH4+) - the primary conditions in the Pliocene basin for the formation of aquifer sand deposits; - for sulfates (SO42-) - washing by underground waters of lignite layers in which sulfides frequently appear, especially in the form of pyrite.

Estilos ABNT, Harvard, Vancouver, APA, etc.

16

Henry, Brian, May Abdel Aziz, Qibing Zhou e Umesh Desai. "Sulfated, low-molecular-weight lignins are potent inhibitors of plasmin, in addition to thrombin and factor Xa: Novel opportunity for controlling complex pathologies". Thrombosis and Haemostasis 103, n.º 03 (2010): 507–15. http://dx.doi.org/10.1160/th09-07-0454.

Texto completo da fonte

Resumo:

SummaryRecently we prepared sulfated, low-molecular-weight lignins (LMWLs) to mimic the biological activities of heparin and heparan sulfate. Chemo-enzymatically prepared sulfated LMWLs represent a library of diverse non-sugar, aromatic molecules with structures radically different from the heparins, and have been found to potently inhibit thrombin and factor Xa. To assess their effect on the fibrinolytic system, we studied the interaction of LMWLs with human plasmin. Enzyme inhibition studies indicate that the three sulfated LMWLs studied inhibit plasmin with IC50 values in the range of 0.24 and 1.3 μM, which are marginally affected in the presence of antithrombin. Similarly, plasmin degradation of polymeric fibrin is also inhibited by sulfated LMWLs. Michaelis-Menten kinetic studies indicate that maximal velocity of hydrolysis of chromogenic substrates decreases nearly 70% in the presence of LMWLs, while the effect on Michaelis constant is dependent on the nature of the substrate. Competitive binding studies indicate that the sulfated LMWLs compete with full-length heparin. Comparison with thrombin-heparin crystal structure identifies an anionic region on plasmin as a plausible sulfated LMWL binding site. Overall, the chemoenzymatic origin coupled with coagulation and fibrinolysis inhibition properties of sulfated LMWLs present novel opportunities for designing new pharmaceutical agents that regulate complex pathologies in which both systems are known to play important roles such as disseminated intravascular coagulation.

Estilos ABNT, Harvard, Vancouver, APA, etc.

17

Selyanina, S. B., e N. V. Selivanova. "Hydrophilic-oleophilic properties of sulfate lignin". Russian Journal of Applied Chemistry 80, n.º 7 (julho de 2007): 1140–44. http://dx.doi.org/10.1134/s1070427207070257.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

18

Salman, Salman, Kurniawan Sinaga, Meutia Indriana, Yessi Febriani e Zulfikar Zulfikar. "Pengaruh fermentasi tepung kulit kopi Oleh Aspergillus oryzae dengan penambahan dua variasi konsentrasi urea dan amonium sulfat terhadap penurunan serat kasar". Journal of Pharmaceutical and Sciences 6, n.º 1 (7 de janeiro de 2023): 167–77. http://dx.doi.org/10.36490/journal-jps.com.v6i1.47.

Texto completo da fonte

Resumo:

Tingginya hasil produksi kopi menyebabkan terjadinya peningkatan jumlah limbah kulit kopi yang dihasilkan, sehingga dibutuhkan inovasi baru untuk mengolah limbah kopi agar dapat bermanfaat dan tidak terbuang. Penelitian bertujuan untuk menurunkan serat kasar pada kulit kopi yang difermentasi menggunakan Aspergillus oryzae untuk menjadi pakan ternak. Penelitian dilakukan dengan metode eksperimental dan deskriptif, memakai bahan uji tepung kulit kopi (Coffea sp.), Aspergillus oryzae, urea, amonium sulfat dan mineral. Tepung kulit kopi difermentasi pada media kering dan media basah, di fermentasi pada suhu kamar selama 24 jam, 48 jam, dan 72 jam. Setelah fermentasi, uji analisis jumlah penurunan serat kasar pada sampel menggunakan uji metode Wendee. Hasil penelitian menunjukkan bahwa fermentasi tepung kulit kopi (Coffea sp.) menggunakan Aspergillus oryzae dengan penambahan urea, amonium sulfat dan mineral dapat menurunkan jumlah serat kasar. Perbedaan media fermentasi menunjukkan bahwa fermentasi pada media basah memberikan hasil penurunan serat kasar yang lebih baik dibandingkan fermentasi pada media kering. Hasil serat kasar media kering sampel N1 sebesar 0,25 gram (25%) dan sampel N2 sebesar 0,22 gram (22%), sedangkan hasil serat kasar media basah sampel N1 sebesar 0,13 gram (13%) dan sampel N2 sebesar 0,11 gram (11%). Fermentasi dengan Aspergillus oryzae menghasilkan ligninase, enzim pemecah lignin yang dapat mendegradasi lignin menjadi senyawa yang lebih sederhana.

Estilos ABNT, Harvard, Vancouver, APA, etc.

19

Cai, Jin Ke, e Yong Sheng Zhang. "The Relative Performance Study of Foam Concrete Straw-Based". Advanced Materials Research 788 (setembro de 2013): 646–50. http://dx.doi.org/10.4028/www.scientific.net/amr.788.646.

Texto completo da fonte

Resumo:

The experiment is to extract lignin from straw as the basic material, then to develop cheap resin. By mechanical foaming, we are to research lignin-based epoxy compounds with commercial foaming agent or sodium lauryl sulfate and the foam stabilizing effect under the experimental condition that adding or not coagulant. The study shows that the actual amount of foam can change the strength and weight of foam concrete to some extent. The results of experimental show that the lignin-based epoxy resins prepared by inexpensive straw can be applied YX-M-8-type foaming agent and the modification of sodium dodecyl sulfate in order to improve the utilization of straw, with great social and economic benefits. CLC:TU522 Document Code:A

Estilos ABNT, Harvard, Vancouver, APA, etc.

20

LI, ZHULIN, SHUAI GAO, LEI TANG, DING LIU, QUN LI, GUOYO TIAN e ZHAOJIANG WANG. "Utilization of palm fiber as papermaking materials: Microscopic structure and chemical pulping". October 2022 21, n.º 10 (1 de novembro de 2022): 543–51. http://dx.doi.org/10.32964/tj21.10.543.

Texto completo da fonte

Resumo:

The microscopic structure and pulping properties of palm fiber were explored. Soda cooking and sulfate cooking were conducted and compared in terms of physical strength of the obtained pulps. Sulfate pulp showed better performance than soda pulp, as indicated by the 23% higher tensile index, 49% higher tear index, and 36% higher burst index. To further elevate physical strength, long fibered pulp (LFP), namely commercial softwood sulfate pulp, was mixed with sulfate pulp of palm fiber at levels from 20% to 50%. At the blend level of 50%, tensile index of 52.13 N•m/g, tear index of 15.63 mN•m2/g, and burst index of 3.42 kPa•m2/g were attained. The lignin in spent liquor from pulping was isolated and characterized. Soda lignin of palm fiber was mainly composed of guaiacyl and syringyl units, and showed weight-average molecular weight of 3616 g/mol.

Estilos ABNT, Harvard, Vancouver, APA, etc.

21

Raghuraman, Arjun, Vaibhav Tiwari, Qian Zhao, Deepak Shukla, Asim K. Debnath e Umesh R. Desai. "Viral Inhibition Studies on Sulfated Lignin, a Chemically Modified Biopolymer and a Potential Mimic of Heparan Sulfate". Biomacromolecules 8, n.º 5 (maio de 2007): 1759–63. http://dx.doi.org/10.1021/bm0701651.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

22

Glyad, V. M., D. A. Ponomarev e N. K. Politova. "Characteristics of residual lignin from sulfate pulp". Russian Journal of Bioorganic Chemistry 37, n.º 7 (20 de novembro de 2011): 849–54. http://dx.doi.org/10.1134/s1068162011070089.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

23

Brandt, Agnieszka, Long Chen, Bart E. van Dongen, Tom Welton e Jason P. Hallett. "Structural changes in lignins isolated using an acidic ionic liquid water mixture". Green Chemistry 17, n.º 11 (2015): 5019–34. http://dx.doi.org/10.1039/c5gc01314c.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

24

Gschwend, Florence J. V., Jason P. Hallett e Agnieszka Brandt-Talbot. "Exploring the Effect of Water Content and Anion on the Pretreatment of Poplar with Three 1-Ethyl-3-methylimidazolium Ionic Liquids". Molecules 25, n.º 10 (15 de maio de 2020): 2318. http://dx.doi.org/10.3390/molecules25102318.

Texto completo da fonte

Resumo:

We report on the pretreatment of poplar wood with three different 1-ethyl-3-methylimidazolium ionic liquids, [EMim][OAc], [EMim][MeSO3], and [EMim][HSO4], at varying water contents from 0–40 wt% at 100 °C. The performance was evaluated by observing the lignin and hemicellulose removal, as well as enzymatic saccharification and lignin yield. The mechanism of pretreatment varied between the ionic liquids studied, with the hydrogen sulfate ionic liquid performing delignification and hemicellulose hydrolysis more effectively than the other solvents across the investigated water content range. The acetate ionic liquid produced superior glucose yield at low water contents, while the hydrogen sulfate ionic liquid performed better at higher water contents and produced a recoverable lignin. The methanesulfonate ionic liquid did not introduce significant fractionation or enhancement of saccharification yield under the conditions used. These findings help distinguish the roles of anion hydrogen bonding, solvent acidity, and water content on ionic liquid pretreatment and can aid with anion and water content selections for different applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

25

Mikova, Nadezhda Mikhaylovna, Vladimir Aleksandrovich Levdansky, Yelena Valentinovna Mazurova e Boris Nikolayevich Kuznecov. "SYNTHESIS AND STUDY OF THE PROPERTIES OF XEROGELS DERIVED FROM SULFATED PINE ETHANOL LIGNIN". chemistry of plant raw material, n.º 1 (16 de março de 2021): 45–54. http://dx.doi.org/10.14258/jcprm.2021018242.

Texto completo da fonte

Resumo:

Organic xerogels based on lignin and tannins isolated from pine bark and wood were first obtained by condensation with formaldehyde and furfuryl alcohol in the presence of hydrochloric acid. The use of pine sulfated ethanol lignin made it possible for the first time to obtain sulfur-containing (up to 1.3% wt.) lignin-(tannin)-formaldehyde and lignin-(tannin)-furfuryl xerogels. The density of the obtained gels increases with the addition of tannins to lignin and varies in the range 0.13–0.39 g/cm3. Xerogels synthesized by condensation with furfuryl alcohol are stronger than those obtained using formaldehyde. The presence of sulfur in xerogels was confirmed by elemental and chemical analysis and IR spectroscopy. It was shown by scanning electron microscopy, that lignin-formaldehyde xerogels are formed from large polymer chains, consisting of interconnected aggregates of micron-sized particles and have large pores. The addition of tannins to the polycondensation system is accompanied by the formation of a more compact spatially crosslinked gel structure. BET method showed that all xerogels have low porosity, and lignin-furfuryl samples have a larger average pore diameter (7.2–14.5 nm) compared to lignin-formaldehyde samples (3.03–6.80 nm).

Estilos ABNT, Harvard, Vancouver, APA, etc.

26

Selyanina, S. B., L. N. Parfenova, M. V. Trufanova e N. V. Selivanova. "Hydrodynamic and surfactant properties of sulfate lignin solutions". Russian Journal of Applied Chemistry 84, n.º 8 (agosto de 2011): 1438–41. http://dx.doi.org/10.1134/s107042721108026x.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

27

Putri, Nita Ariestiana, Muhammad Mufti Azis e Suryo Purwono. "A Comparison of Sodium Lignosulfonate (SLS) Synthesis from Black Liquor Lignin and Commercial Lignin". Materials Science Forum 948 (março de 2019): 206–11. http://dx.doi.org/10.4028/www.scientific.net/msf.948.206.

Texto completo da fonte

Resumo:

Sulphonation of lignin has been considered as a promising step to produce lignosulfonate which may serve as dispersant, flocculant, and surfactant. The aim of present study was to compare the synthesis of sodium lignosulfonate (SLS) from different lignin feedstocks namely commercial lignin and lignin isolated from black liquor (BL) of pulp and paper industry. A novel technique to isolate lignin from BL was introduced with the aid of CO2 and coagulant of alumunium sulfate. The FTIR spectra of BL lignin showed similarity with commercial lignin which indicates that the isolation of BL lignin with the present technique did not alter the chemical structure of lignin. Furthermore, sulphonation of commercial and BL lignin with NaHSO3 solution has been conducted to obtain SLS powder. In general, the FTIR spectra of SLS from commercial and BL lignin were similar to their parent lignin. However, absorption peak which corresponds to SO3 vibration was lightly detected on both samples which indicated the insertion of SO3 functional group into the lignin structure. The ability of SLS to increase the oil mobility for Enhanced Oil Recovery (EOR) was measured from the interfacial tension (IFT). Our results showed that the IFT values of SLS solution from commercial lignin and BL lignin were 0.3759 mN/m and 0.2675 mN/m, respectively. Further formulation of SLS from BL lignin with octanol and PFAD solution may lower the IFT value to 0.0186 mN/m.

Estilos ABNT, Harvard, Vancouver, APA, etc.

28

Karp, Susan Grace, Vincenza Faraco, Antonella Amore, Luiz Alberto Junior Letti, Vanete Thomaz Soccol e Carlos Ricardo Soccol. "Statistical Optimization of Laccase Production and Delignification of Sugarcane Bagasse byPleurotus ostreatusin Solid-State Fermentation". BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/181204.

Texto completo da fonte

Resumo:

Laccases are oxidative enzymes related to the degradation of phenolic compounds, including lignin units, with concomitant reduction of oxygen to water. Delignification is a necessary pretreatment step in the process of converting plant biomass into fermentable sugars. The objective of this work was to optimize the production of laccases and to evaluate the delignification of sugarcane bagasse byPleurotus ostreatusin solid-state fermentation. Among eight variables (pH, water activity, temperature, and concentrations of CuSO4, (NH4)2SO4, KH2PO4, asparagine, and yeast extract), copper sulfate and ammonium sulfate concentrations were demonstrated to significantly influence laccase production. The replacement of ammonium sulfate by yeast extract and the addition of ferulic acid as inducer provided increases of 5.7- and 2.0-fold, respectively, in laccase activity. Optimization of laccase production as a function of yeast extract, copper sulfate, and ferulic acid concentrations was performed by response surface methodology and optimal concentrations were 6.4 g/L, 172.6 μM, and 1.86 mM, respectively. Experimentally, the maximum laccase activity of 151.6 U/g was produced at the 5th day of solid-state fermentation. Lignin content in sugarcane bagasse was reduced from 31.89% to 26.36% after 5 days and to 20.79% after 15 days by the biological treatment of solid-state fermentation.

Estilos ABNT, Harvard, Vancouver, APA, etc.

29

Ghavidel Darestani, Nasim, Adrianna Tikka e Pedram Fatehi. "Sulfonated Lignin-g-Styrene Polymer: Production and Characterization". Polymers 10, n.º 8 (19 de agosto de 2018): 928. http://dx.doi.org/10.3390/polym10080928.

Texto completo da fonte

Resumo:

Among sustainable alternatives for replacing fossil-based chemicals, lignin is widely available on earth, albeit the least utilized component of biomass. In this work, lignin was polymerized with styrene in aqueous emulsion systems. The reaction afforded a yield of 20 wt % under the conditions of 100 g/L lignin concentration, pH 2.5, 0.35 mol/L sodium dodecyl sulfate concentration, 5 mol/mol styrene/lignin ratio, 5 wt % initiator, 90 °C, and 2 h. The lignin-g-styrene product under the selected conditions had a grafting degree of 31 mol % of styrene, which was determined by quantitative proton nuclear magnetic resonance (NMR). The solvent addition to the reaction mixture and deoxygenation did not improve the yield of the polymerization reaction. The produced lignin-g-styrene polymer was then sulfonated using concentrated sulfuric acid. By introducing sulfonate group on the lignin-g-styrene polymers, the solubility and anionic charge density of 92 wt % (in a 10 g/L solution) and −2.4 meq/g, respectively, were obtained. Fourier-transform infrared (FTIR), static light scattering, two-dimensional COSY NMR, elemental analyses, and differential scanning calorimetry (DSC) were also employed to characterize the properties of the lignin-g-styrene and sulfonate lignin-g-styrene products. Overall, sulfonated lignin-g-styrene polymer with a high anionicity and water solubility was produced.

Estilos ABNT, Harvard, Vancouver, APA, etc.

30

Smirnova, Anastasiya Igorevna, Alla Borisovna Dyagileva, Aleksandra Yevgen'yevna Prismakova e Ol'ga Yur'yevna Derkacheva. "INFLUENCE OF LIGNIN CONCENTRATION ON VISCOELASTIC PROPERTIES OF ITS MODIFIED FORM OB-TAINED BY SOL-GEL METHOD IN THE PRESENCE OF ALUMINUM-SILICON COMPOUNDS". chemistry of plant raw material, n.º 3 (27 de setembro de 2021): 123–33. http://dx.doi.org/10.14258/jcprm.2021038697.

Texto completo da fonte

Resumo:

The concept and flow model of a structured dispersed system obtained on the basis of sulfate lignin modified by Sol-gel method in the presence of aluminum-containing components in the form of nepheline concentrate are considered. The systems are mainly systems of non-Newtonian behavior, characterized by phenomena of destruction and formation of new structures in the shear flow, and the nature of the flow depends on the characteristics of interaction between system components, which are defined as their concentrations, and process conditions of the synthesis, at which the change of the adhesion forces between particles and at the moment cannot be generalized and described existing well-known equations of flow.As a result of the study, it was found that an increase in the concentration of sulfate lignin under various synthesis conditions, but with a constant amount of mineral component, leads to the formation of a new modified product, while there is a tendency to increase the parameters of kinematic viscosity and shear stress at the corresponding pH values of synthesis. Under conditions of excessive lignin concentrations of more than 400 mg/dm3, when self-organizing in the matrix of a new form, lignin dominance leads to a decrease in the strength characteristics of the polymer for all its forms obtained at different pH values. It is established that the kinematic viscosity and shear stress of water dispersions in this system depend on both the pH value of their synthesis and the concentration of the initial lignin, which determines the mechanisms of self-organization of the new modified structure.

Estilos ABNT, Harvard, Vancouver, APA, etc.

31

Danshina, К., e Т. Filonenko. "FEATURES OF A COMPREHENSIVE FORENSIC RESEARCH OF HYDROLYZED LIGNIN". Theory and Practice of Forensic Science and Criminalistics 19, n.º 1 (2 de junho de 2019): 503–10. http://dx.doi.org/10.32353/khrife.1.2019.40.

Texto completo da fonte

Resumo:

The article deals with the peculiarities of complex expert research of lignin, since knowledge of the forensic and chemical and forensic examinations was required. It was noted that in the microscopic study, all of the samples submitted for research revealed small particles of brown wood with different shades and brown conglomerates. The maceration method investigated specially processed samples of the substances provided. A qualitative reaction to lignin revealed the presence of molecules provided for the study of substances, the conifer aldehyde group and the structural chain that is characteristic of lignin. Qualitative reactions revealed that iron, calcium, magnesium, aluminum and sulfate ions were identified in all lignin samples, which characterizing qualitative composition of vegetable raw materials. It has been determined that further studies of lignin should be carried out in a well-established manner, namely: determination of carbon content; quantitative determination of solids and hygroscopic moisture; determination of ash content; determination of the quantitative content of calcium; quantitative determination of magnesium; determination of quantitative content of iron.

Estilos ABNT, Harvard, Vancouver, APA, etc.

32

Norgren, Magnus, e Sofia Mackin. "Sulfate and Surfactants as Boosters of Kraft Lignin Precipitation". Industrial & Engineering Chemistry Research 48, n.º 10 (20 de maio de 2009): 5098–104. http://dx.doi.org/10.1021/ie900141s.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

33

Luo, Zhicheng, e Chen Zhao. "Mechanistic insights into selective hydrodeoxygenation of lignin-derived β-O-4 linkage to aromatic hydrocarbons in water". Catalysis Science & Technology 6, n.º 10 (2016): 3476–84. http://dx.doi.org/10.1039/c5cy01434d.

Texto completo da fonte

Resumo:

The route for selective hydrodeoxygenation of phenethoxybenzene (PEB, which represents the dominant β-O-4 linkage in lignin) to produce benzene and ethylbenzene is realized by employing a multi-functional Ru/sulfate zirconium (Ru/SZ) catalyst in the aqueous phase.

Estilos ABNT, Harvard, Vancouver, APA, etc.

34

Azhar, Nur Amalina, Sabrina Soloi, Rohah A. Majid e Jamarosliza Jamaluddin. "Grafting Efficiency of Lignin-Grafted-Polyacrylic Acid". Applied Mechanics and Materials 735 (fevereiro de 2015): 182–85. http://dx.doi.org/10.4028/www.scientific.net/amm.735.182.

Texto completo da fonte

Resumo:

Agriculture biomasses have been successfully converted into value-added products such as biocomposite plastics, furniture, papers and textiles. However, only the cellulose parts of these lignocellulosic materials are being used while other components such as lignin and wax are discarded. For a tropical country like Malaysia, banana stem is one of the sources of biomasses. Like other biomasses-based products, only cellulose part of banana stem is used while the lignin portion is discarded due to overly hydrophilic character. This water-loving property of lignin can be manipulated into specific application such as water absorbent for waste treatment. This research is aimed to synthesis water absorbent-based lignin from banana stem. The lignin had been extracted from banana stem using Kraft process prior to grafted with acrylic acid monomer (AA) in order to increase its water absorbency. The reaction was carried out via free radical polymerization in the presence of hydrogen peroxide (H2O2) as initiator and ammonium iron (II) sulfate hexahydrate as catalyst. The reaction temperature was set at 60°C. Grafting efficiency of polyacrylic acid (PAA) onto lignin backbone was determined by varying the amounts of AA monomer, lignin and initiator. The highest grafting percentage was acquired at 60% with the amount of 6ml acrylic acid, 2ml initiator and 0.2g lignin respectively.

Estilos ABNT, Harvard, Vancouver, APA, etc.

35

Luo, Zhicheng, Yimeng Wang, Mingyuan He e Chen Zhao. "Precise oxygen scission of lignin derived aryl ethers to quantitatively produce aromatic hydrocarbons in water". Green Chemistry 18, n.º 2 (2016): 433–41. http://dx.doi.org/10.1039/c5gc01790d.

Texto completo da fonte

Resumo:

To produce aromatic hydrocarbons from biomass, a novel route is reported for one-pot selective hydrodeoxygenation of a lignin derived aryl ether mixture to C₆–C₉ aromatic hydrocarbons over Ru/sulfate zirconia in the aqueous phase.

Estilos ABNT, Harvard, Vancouver, APA, etc.

36

Detmers, J., U. Schulte, H. Strauss e J. Kuever. "Sulfate Reduction at a Lignite Seam: Microbial Abundance and Activity". Microbial Ecology 42, n.º 3 (1 de outubro de 2001): 238–47. http://dx.doi.org/10.1007/s00248-001-1014-8.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

37

Febriani, Cindy Yulia. "HIDROLISIS LIGNOSELULOSA DAN KARAKTERISASI LIGNIN DARI MATERIAL LIMBAH KELAPA DENGAN METODE HIDROLISIS ASAM SULFAT". Jurnal Teknologi Kimia Unimal 10, n.º 2 (30 de novembro de 2021): 45. http://dx.doi.org/10.29103/jtku.v10i2.5573.

Texto completo da fonte

Resumo:

Penelitian ini melakukan hidrolisis lignoselulosa menggunakan asam sulfat dengan limbah kelapa berupa batok dan sabut kelapa untuk memeroleh zat lignin. Rasio padatan:larutan yang digunakan sebesar 3:25 (m/v). Variasi waktu pemanasan 2 hingga 5 jam. Lignin tidak larut asam yang diperoleh diuji karakterisasi menggunakan FT-IR dan SEM. Rata-rata yield lignin tidak larut dan larut asam pada batok kelapa lebih besar daripada sabut kelapa. Gugus metoksil menghilang setelah hidrolisis, gugus guaiasil terdeteksi pada batok kelapa setelah proses hidrolisis, adanya cincin aromatik yang berkaitan dengan lignin pada masing-masing sampel sebelum dan setelah hidrolisis, serta gugus siringil pada sabut kelapa sebelum dan setelah proses hidrolisis.

Estilos ABNT, Harvard, Vancouver, APA, etc.

38

Ko, Jae-Jung, Yoshihisa Shimizu, Kazuhiro Ikeda, Seog-Ku Kim, Chul-Hwi Park e Saburo Matsui. "Biodegradation of high molecular weight lignin under sulfate reducing conditions: Lignin degradability and degradation by-products". Bioresource Technology 100, n.º 4 (fevereiro de 2009): 1622–27. http://dx.doi.org/10.1016/j.biortech.2008.09.029.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

39

Chen, Yuanhang, Zhenyun Yan, Long Liang, Miao Ran, Ting Wu, Baobin Wang, Xiuxiu Zou, Mengke Zhao, Guigan Fang e Kuizhong Shen. "Comparative Evaluation of Organic Acid Pretreatment of Eucalyptus for Kraft Dissolving Pulp Production". Materials 13, n.º 2 (12 de janeiro de 2020): 361. http://dx.doi.org/10.3390/ma13020361.

Texto completo da fonte

Resumo:

Pretreatment is an essential process for the extensive utilization of lignocellulose materials. The effect of four common organic acid pretreatments for Kraft dissolving pulp production was comparatively investigated. It was found that under acidic conditions, hemicellulose can be effectively removed and more reducing sugars can be recovered. During acetic acid pretreatment, lignin that was dissolved in acetic acid could form a lignin-related film which would alleviate cellulose hydrolysis, while other organic acids caused severe cellulose degradation. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) were used to characterize the pretreated chips in the process. Lignin droplets were attached to the surface of the treated wood chips according to the SEM results. The FTIR spectrum showed that the lignin peak signal becomes stronger, and the hemicellulose peak signal becomes weaker with acid pretreatment. The XRD spectrum demonstrated that the crystallinity index of the wood chips increased. The acetic acid pretreatment process-assisted Kraft process achieved higher yield (31.66%) and higher α-cellulose (98.28%) than any other organic acid pretreatment. Furthermore, extensive utilization of biomass was evaluated with the acetic acid pretreatment-assisted Kraft process. 43.8% polysaccharide (12.14% reducing sugar and 31.66% dissolving pulp) and 22.24% lignin (0.29% acetic acid lignin and 21.95% sulfate lignin) were recovered during the process. Biomass utilization could reach 66.04%. Acetic acid pretreatment is a promising process for extensive biomass utilization.

Estilos ABNT, Harvard, Vancouver, APA, etc.

40

Jiménez Montoya, Jesús Alvaro, Bibiana Gordillo Díaz e Marco Antonio Vega Atuesta. "Modificación estructural de la lignina extraída a partir de carbones de bajo rango para la obtención de madera sintética". Revista Tecnura 15, n.º 28 (19 de junho de 2012): 68. http://dx.doi.org/10.14483/udistrital.jour.tecnura.2011.1.a06.

Texto completo da fonte

Resumo:

El grupo Investigación en Carbones de la Universidad Distrital Francisco José de Caldas ha trabajado en la extracción de lignina a partir de carbón de bajo rango y de turba, con el fin de emplearla en la elaboración de madera sintética y de esta manera aplicarla a la industria maderera.En una primera parte se aplicaron los métodos Sosa, Sulfato y Bisulfito [1], modificados para la extracción de lignina a partir de pino y cedro, se evidenció que el método Sosa era el de mayor rendimiento. Este método fue aplicado para la extracción de liglina a partir de una muestra de carbón leonardítico. Posteriormente, ésta se utilizó en la elaboración de [a resina lignina-fenol-formaldehído, la cual actúa como aglomerante de fibras naturales [2].La segunda parte se fundamentó en la estandarización del método Sosa [3], en el cual se modificó la presión utilizando autoclave para una muestra de turba, lo cual mejoró el rendimiento. La lignina obtenida se empleó en la elaboración de resinas tales como lignina-fenol-formaldehído, lignina-resorcinol-formaldehído y lignina-polipropileno, las cuales fueron utilizadas empleando como fibra natural bagazo de caña.

Estilos ABNT, Harvard, Vancouver, APA, etc.

41

Raghuraman, Arjun, Vaibhav Tiwari, Jay N. Thakkar, Gunnar T. Gunnarsson, Deepak Shukla, Michael Hindle e Umesh R. Desai. "Structural Characterization of a Serendipitously Discovered Bioactive Macromolecule, Lignin Sulfate". Biomacromolecules 6, n.º 5 (setembro de 2005): 2822–32. http://dx.doi.org/10.1021/bm0503064.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

42

Yan, Qiangu, Jinghao Li, Xuefeng Zhang, Jilei Zhang e Zhiyong Cai. "Synthetic Bio-Graphene Based Nanomaterials through Different Iron Catalysts". Nanomaterials 8, n.º 10 (16 de outubro de 2018): 840. http://dx.doi.org/10.3390/nano8100840.

Texto completo da fonte

Resumo:

Kraft lignin was catalytically graphitized to graphene-based nanostructures at 1000 °C under argon atmosphere with four iron catalysts, iron(III) nitrate (Fe-N); iron(II) chloride (Fe-Cl2); iron(III) chloride (Fe-Cl3); and iron(II) sulfate (Fe-S). The catalytic decomposition process of iron-promoted lignin materials was examined using thermalgravimetric analysis and temperature-programmed decomposition methods. The crystal structure, morphology and surface area of produced materials were characterized by means of X-ray diffraction, Raman, scanning electron microscopy, high resolution transmission electron microscopy and N2 adsorption−desorption techniques. Experimental results indicated that iron nitrate catalyst had better iron dispersion three other iron salts. Iron nitrate was the most active catalyst among four iron salts. The low activity of iron in iron chloride-promoted samples was because the residual chlorine over iron surfaces prevent iron interaction with lignin functional groups.

Estilos ABNT, Harvard, Vancouver, APA, etc.

43

Henry, Brian L., Justin Connell, Aiye Liang, Chandravel Krishnasamy e Umesh R. Desai. "Interaction of Antithrombin with Sulfated, Low Molecular Weight Lignins". Journal of Biological Chemistry 284, n.º 31 (4 de junho de 2009): 20897–908. http://dx.doi.org/10.1074/jbc.m109.013359.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

44

Albis Arrieta, Alberto Ricardo, Maria Cecilia Romero Castilla, Ever Ortiz Muñoz, Ismael Enrique Piñeres Ariza e Edgar Fabian Donado Medina. "Devolatilization of African Palm (Elaeis guineensis) Husk Catalyzed by Ferrous Sulfate Studied by TG-MS". Ingeniería e Investigación 42, n.º 3 (26 de agosto de 2022): e90946. http://dx.doi.org/10.15446/ing.investig.90946.

Texto completo da fonte

Resumo:

By means of a thermogravimetric analysis coupled with mass spectroscopy, the catalytic effect of ferrous sulfate on the pyrolysis of African Palm husk (APH) was studied. Thermogravimetric data were adjusted to the distributed activation energy model (DAEM) with four pseudo-components. Ferrous sulfate had a strong influence on the decomposition parameters of the second and fourth pseudo-components of the DAEM, which are identified as hemicellulose and lignin, respectively. The profiles of the signal intensity curves for the selected m/z ratios were successfully modeled using the kinetic parameters obtained by adjusting the thermogravimetric data. It was found that ferrous sulfate promotes the formation of fragments of m/z = 64, 95, and 96, corresponding to molecules, such as SO2, hydrocarbon ions of general formula [CnH2n‑3]+, and furfural, respectively.

Estilos ABNT, Harvard, Vancouver, APA, etc.

45

Jiang, Huabin, Jiaqi Nie, Lei Zeng, Fei Zhu, Zhongwang Gao, Aiping Zhang, Jun Xie e Yong Chen. "Selective Removal of Hemicellulose by Diluted Sulfuric Acid Assisted by Aluminum Sulfate". Molecules 29, n.º 9 (28 de abril de 2024): 2027. http://dx.doi.org/10.3390/molecules29092027.

Texto completo da fonte

Resumo:

Hemicellulose can be selectively removed by acid pretreatment. In this study, selective removal of hemicellulose was achieved using dilute sulfuric acid assisted by aluminum sulfate pretreatment. The optimal pretreatment conditions were 160 °C, 1.5 wt% aluminum sulfate, 0.7 wt% dilute sulfuric acid, and 40 min. A component analysis showed that the removal rate of hemicellulose and lignin reached 98.05% and 9.01%, respectively, which indicated that hemicellulose was removed with high selectivity by dilute sulfuric acid assisted by aluminum sulfate pretreatment. Structural characterizations (SEM, FTIR, BET, TGA, and XRD) showed that pretreatment changed the roughness, crystallinity, pore size, and functional groups of corn straw, which was beneficial to improve the efficiency of enzymatic hydrolysis. This study provides a new approach for the high-selectivity separation of hemicellulose, thereby offering novel insights for its subsequent high-value utilization.

Estilos ABNT, Harvard, Vancouver, APA, etc.

46

Prismakova, A. E., A. B. Dyagileva e A. I. Smirnova. "Rheological Properties of Sulfate Lignin Modified by the Sol-Gel Method". Bulletin of Higher Educational Institutions. Lesnoi Zhurnal (Forestry journal), n.º 3 (10 de maio de 2018): 137–48. http://dx.doi.org/10.17238/issn0536-1036.2018.3.137.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

47

Khabarov, Yu G., N. Yu Kuzyakov, V. A. Veshnyakov, G. V. Komarova e A. Yu Garkotin. "Nitration of sulfate lignin under homogeneous conditions studied by electron spectroscopy". Russian Chemical Bulletin 65, n.º 12 (dezembro de 2016): 2925–31. http://dx.doi.org/10.1007/s11172-016-1679-2.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

48

Barclay, L. Ross C., Jennifer K. Grandy, Heather D. MacKinnon, Heather C. Nichol e Melinda R. Vinqvist. "Article". Canadian Journal of Chemistry 76, n.º 12 (1 de dezembro de 1998): 1805–16. http://dx.doi.org/10.1139/v98-209.

Texto completo da fonte

Resumo:

3,5-Di-tert-butyl-ortho-quinone, 6, and 1-(3,4-dimethoxyphenyl-2-(2-methoxyphenoxy)-1-propanone, 7, models for oxidized lignin and for lignin, were used as sensitizers of photo-oxidation. Product studies by HPLC from oxidation of methyl linoleate in solution sensitized by 6 or 7, and in sodium dodecyl sulfate (SDS) sensitized by 6, showed a product distribution of six hydroperoxides, the four conjugated 9- and 13-hydroperoxides of the geometrical isomers: trans-10, cis-12 (2), cis-9, trans-11 (3), trans-10, trans-12 (4), and trans-9, trans-11 (5)-octadecadienoates plus two nonconjugated hydroperoxides. The higher cis/trans to trans/trans (ct/tt) of geometrical isomers (2 + 3//4 + 5) compared to ct/tt from known thermal free-radical peroxidations (Type 1) indicate that singlet oxygen (Type 2) oxidation occurs in reactions sensitized by 6 or 7. Kinetic studies by oxygen uptake are reported on oxidations of hydrocarbons 1-phenyl-2-methylpropene,8, and trans-stilbene,9, sensitized by the quinone, 6, or by a dye, Rose Bengal. Quenching studies imply singlet oxygen reactions. Milled wood lignin undergoes self-initiated photo-oxidation in water, and oxygen uptake was quenched by sodium azide. Cellobiose, a cellulose model, undergoes sensitized photo-oxidation using model quinone, 6, in a mixture of tert-butyl alcohol and water or using the sensitizers benzophenone or the lignin model, 7, delivered on a solid support, silica gel, and these oxidations were quenched with sodium azide. These results implicate singlet oxygen in the photo-yellowing of high lignin content wood pulps.Key words: lignin models, ortho-quinone, photo-oxidation, singlet oxygen, lignin, cellobiose.

Estilos ABNT, Harvard, Vancouver, APA, etc.

49

MACHADO VIANA CRUZ, VITOR, e JOSÉ VICENTE HALLAK DANGELO. "Eucalyptus black liquor properties in a lignin extraction process: density, dry solids, viscosity, inorganic, and organic content". March 2023 22, n.º 3 (1 de abril de 2023): 151–60. http://dx.doi.org/10.32964/tj22.3.151.

Texto completo da fonte

Resumo:

Extracting lignin from black liquor is becoming more common, although only a few research papers discuss the impact of the process on the liquor’s primary properties. This work aims to determine the changes in black liquor properties as it undergoes a lignin extraction process using carbon dioxide (CO2). A diluted eucalyptus black liquor sample (DBL) was acidified with CO2 to a final pH of 8.5. After filtration, the kraft lignin was removed, and the filtrated lignin lean black liquor (LLBL) was collected. Five acidified black liquors (ABL) samples were collected during acidification at pH 10.5; 10.0; 9.5; 9.0; and 8.5. The samples were analyzed regarding lignin content in solution, sodium carbonate (Na2CO3), sodium sulfate (Na2SO4), density, dry solids content, and viscosity. While Na2SO4 remained almost constant, Na2CO3 presented an enormous increase in its concentration when comparing DBL with LLBL. As pH decreased, the lignin content in the solution was also reduced due to lignin precipitation. The results showed similar behavior for dry solids, density, and viscosity of the supernatant, but an increase in density was observed around pH 9.00. In light of this, the density of LLBL turns out to be closer to the one in the initial DBL. The significant increase in carbonate content could explain this behavior during acidification with CO2 once the inorganic content significantly influences the property. The viscosity was determined from 10 s−1 to 2000 s−1. We observed a Newtonian behavior for all samples. The increase in carbonate content in the sample is crucial information to the recovery cycle, especially for calculating the mass and energy balance when targeting the use of the LLBL.

Estilos ABNT, Harvard, Vancouver, APA, etc.

50

Chen, Xuanlai, Guochao Yan, Xianglin Yang e Guang Xu. "Study on Adsorption Characteristics of Sulfonate Gemini Surfactant on Lignite Surface". Minerals 11, n.º 12 (11 de dezembro de 2021): 1401. http://dx.doi.org/10.3390/min11121401.

Texto completo da fonte

Resumo:

In order to explore the adsorption characteristics of sulfonate gemini surfactants on the surface of lignite, the molecular dynamics simulation method was used, and A kind of sulfonic acid bis sodium salt (S2) and the sodium dodecyl sulfate (SDS) were selected. A binary model of surfactant/lignite adsorption system and a ternary model of water/surfactant/lignite system were constructed, and a series of properties such as adsorption configuration, interaction energy, order parameters, relative concentration distribution, number of hydrogen bonds, etc., were analyzed. The results showed that the adsorption strength of S2 on the surface of lignite was higher than that of SDS. The results indicated that the large-angle molecular chain in S2 tended to become smaller, the small-angle molecular chain tended to become larger, and the angle between the molecular chains and the Z axis tended to be concentrated, making the formed network structure denser during the adsorption process. The number of hydrogen bonds in the water-coal system was 42, and the number of hydrogen bonds in the system after S2 adsorption was 15, which was much lower than the 23 hydrogen bonds in the system after SDS adsorption, and S2 could better adsorb and wrap the oxygen-containing groups on the surface of the lignite. The comparative study of the adsorption characteristics of the two surfactants on the surface of lignite can help us better understand the influence of the surfactant structure on the adsorption strength. The research results have important theoretical and practical significance for developing new surfactants, and enriching and developing the basic theory of coal wettability.

Estilos ABNT, Harvard, Vancouver, APA, etc.

Artigos de revistas sobre o tema "Lignine sulfatée"

Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos